Duplicating



Patented Nov. 9, 1926.

vUIT

DAVID GESTETNER, or LONDON, ENGLAND, AssIGNoR To D. GESTETNER, LIMITED, o'E

TOTTENHAM HALEfL'ONDON, ENGLAND. I

DUPLICATING.

Application filed rebrary as, 192e, serial No.

' This invention relates to duplicating with the aid of' stencils formed by the local application to a stencil sheet, c onsistlng vof a highly porous material 'furnished with an ink-resisting coating, of a material adapted to soften .the coating or otherwise change its character so that by. subsequent treat-- ment tli'e portion of the coating so treated may be removed.

.'lhe production of stencils forA use in the duplication of handwriting, drawings and the like in this particular manner has not been whollysuccessful owing to the tendency of the materials employed for locally softening yand removing the coating composition (and which will hereinafter be referred to as liquefying agents) to spread.

For coarse work the spreading of the liquefying agent may not constitute a Aserious defect but when it is desired to produce impressions of handwriting, drawings or the like the spreading of the liquefying agent has a most unfavourable result, the lines in the impressions obtained being heavy or coarse and blurred at their edges.

An observation upon which the present invention is based is that when intimate contact between the stencil Sheet and an absorbent or relatively absorbent support or backing is obtained, by securing adhesion between the stencil sheet and the support or backing,-when applying the liquefying agent to thevstencil sheet, the spreading of the liquefying agent and the consequent irregular action thereof could be minimized.

This observationsuggests that the desirable results obtained when adhesion between the stencil sheet and backing orsupport is secured were to be attributed solely tothe fact that by securing such adhesion the passage pf excess of liquefying agent into the substance of the backing sheet was facilitated and thus the lateral spreading of the same was minimized.

Further experiment carried out with the object of lindng a suitable composition for stencil sheets of the character in which, to take a specific instance, a gelatine compostion was applied to one face of a sheet of yoshino paper while a wax composition was applied to the other, showed that while there was thus obtained a certain degree of adhesion between the stencil sheet and backing quite good results were secured even 90,930, and in Great Britain January 21, 1925.

when the support employed was quite impern'xeable. The use of a coloured wax com' position showed that the pressure ofthe pen used in writing causedthe composition to be transferred locally to the support and this seemed to. indicate that the wax composition might actually constitute the eiective ink-resisting medium of the finished stencil.

yThe adhesive or transferring composition would seem to be preferably one which will not be` affected by the liquefying agents used, while it would seem essential that the degree of adhesion obtained should at least be of such character that where pressure is exerted locally on the stencil sheet by the instrument used in applying the liquefying agent the transferring composition would be caused to adhere to the support for the stencil sheet ifl only' to a degree to secure the local transference of the said composition. to the support.

It furthermore appears desirable generally to employ an absorbent or relatively absorbent support for the stencil sheet during the operation of forming the stencil so adapted to be liquefied or solubilized, comprises securing adhesion between the back of the stencil sheet and the support or backing therefor during the operation of apply- A ing the liquefying or solubilizing agent locally to the stencil sheet. i f

The desired degree of adhesion may be secured in any convenient manner as, for instance, by providing between the stencil sheet vand the backing a Elm of material adapted to cause the stencil sheet to adhere to the backing. I

Normally, if not invariably, the material employed to secure adhesion is of such character that the' pressure of the implement used in delineatin lines' or signs on the stencil sheet causes the back of the latter to adhere to the support the characters,

only at or adjacent to those (points where suc pressure has been applic lar methods of securing the location of the adhesive material between the stencil sheet and the support but generally it will be found convenient either to coat suitably the back of the stencil sheet or the face of the support with the adhesive material or th.

A wide variety of adhesive or transferring materials may be used without exceeding the scope of the application.` For-instance,

waxy compositions or water-insoluble adhesives may be employed and while these it might be thoughtwould impede the absorption of the liquefying agent by the porous or absorbent support when such are used it is found that they do not do so to any material extent, this being. probably due to the fact that the liquefying agent is absorbed by the portions of the absorbent support in the im'- mediate vicinity of those to which the coating of adhesive or transferring material adheres or to which it is transferred-in the stencilizing operation.

In carrying the method in accordance with the invention into effect the back of the stencil sheet or the adjacent face of the support may be treated to secure the desired ady hesion immediately prior to the operation of forming the stencil. Considerations of a practical nature, however, render it desirable for the manufacturer to place in the hands of the user an article which needs the minimum of manipulation or treatment.

The invention also extends to improved stencil sheets adapted to be stencilized by the local application of a liquefying agent.

A stencil sheet in accordance with the invention comprises an ink-resisting film adapted to be softened by a liquefying agent usedin forming the stencil, coated on a highly porous material or material of openwork texture, the back of which' is provided with a coating or layer of an adhesive character,

I being preferably sutliciently adhesive to adhere to the backing in contact with which the stencil sheet is secured only at or adjacent to those points where pressure is applied to the sheet in the operation of forming the stencil, or with a coating which is not necessarily adhesive but which will be transferred to the support at or adjacent to such points.

The invention also consists in a combined stencil sheet including a stencil sheet comprising an ink-resisting adapted to be softened by the action of an lagent used in Y:forming )the stencil, coated on a highly porous material or material of openwork texture, a backing sheet detachably connected therewith and a film of adhesive or transferring material between the stencil sheet and the backing sheet.

In a combined stencil' .sheet in accordance with the invention Athe adhesiveA or transfer- 1 which are not in some senses adhesive may v be used; such compositions must, however, be of such 'character that they may be transferred and will hence adhere to the support.

`Wax compositions which are not sticky but resemble the wax compositions used in 'coating co-called carbon papers may be cited as examples of materials which may be employed in accordance with the invention which are not sticky or tacky.

lVhere the ink-resisting layer or coating of the'stencil is adapted to be softened by v an aqueousliquefying agent the adhesive/material may be water soluble or it may be insoluble in-water.

A mixture comprising glucose (corn syrup) and glycerine may be mentioned as an `example of an adhesive material of a tacky nature solublein water; elemi, Canada balsam, polymerized fatty oils, nitrated nondrying oils, waxes and compositions derived from these materials may be mentioned as examples of materials of an adhesive character which are insoluble in Water.' It is, however, to be understood that the invention is not confined-to the use of the specific materials mentioned as adhesives, as many other substances or compositions than `those mentioned may be employed, although preferably where the liquefying or solubilizing agent is of an aqueous character adhesive or transferring materials insoluble or relatively insoluble in aqueous media are employed. A further feature ofthe invention consists in impregnating thev absorbent orV relatively absorbent backing with a material adapted to render the same translucent or transparent Without inhibitin its capacity to absorb the softening, liquefying or solubilizing agent.

` In accordance with this feature of the invention the backing may bef'treated with Wool wax (adcps lante) -or an equivalent material.

A combined stencil sheet embodying thisl feature will be adapted for use .in tracing as the treated backing sheet being transparlll() recaer? ent or translucent will enable the matter below the sheet to be seen and therefore traced and the material with which the backing is treated will prevent the liquefying or material insoluble in the ingredients of the composition employed in forming the coating. Y

The addition of kieselguhr, china-clay or a highly colloidal clay, such as the material known as Bentonite, or of zinc oxide, lithopone or the like, appears to have a de` sirable effect in reducing the tendency of the liquefying agent to spread. i

In part, this effect may be due to the fact that the materials in question impart a matt surface to the coating.

In addition, certain materials which are suitable for use tend to neutralize the action of the liquefying agent and such materials may be included also in the adhesive or transferring composition. instance, a solution of sulphuric acid is employed as the liquefyng agent, gelatine being the main constitutent of the ink-resisting composition of the` stencil sheet, the presence of zinc oxide in the composition will neutralize the acid tending to spread itself laterally in the ink-resisting coating.

The invention is not confined to the' employment of any specific material in forming the coating composition; generally, however, a elatinizing organic colloid will be used and conveniently a proteinis employed.

With proteins, a variety'of bodies includedin the so-called Hofmeister series may be used as the liquefying agent.

A 50 per cent'solution of sulphuric acid suitably coloured may` for example,v be employed as the liquefying agent.

The highly porous material which is furnished with the ink-resisting coating may be yoshino paper, now universally used in they manufacture of stencil sheets for use in duplicating; alternatively. iine lawn may be employed should the character of the material to be reproduced admit of the use of a woven fabric.

In forming a stencil in accordance with the invention it will be found that the softening agent rapidly penetratesv the ink-resisting medium, the excess being absorbed by the backing in which it usually spreads laterally without, however, the absorbed material detrimentally affecting the portions of the ink-resisting medium on the adiacentV portions of the stencil sheet.

The absorptive properties of the backing need not be considerable, paper which when written on in the ordinary way with ink absorbs merely the ink normally delivered by the pen without the absorbed ink spread- Thus when, for l ing materially in a lateral direction being quite suitable, the use of highly absorbent paper such as blotting paper being unnecessary.

ln fact, the use of absorbent material asl the support orbacking may be dispensed with in some cases, as has been pointed out above.

The ink-resisting composition of the stencil sheet must be employed as a very -thin layer or .coating if the besty results are to be secured.

ln some cases it mayy be desirable or convenient to incorporate in the adhesive material a pigment, for ,instance a lightcoloured opaque pigment` which will have the effect of rendering the material cut 1n the stencil visible when the latter is mounted in contact with the inking means of a dupf licating machine.

The following particulars are given by way of example for the purpose of describing a convenient manner of carrying the invention into effect:-

Yoshino paper in sheets is coated by drawing over a roller partly immersed in the following compositiom- Pf? il?" Gelatine g Water 670 Alum 025 Glycerine 15 Potassium oleate 7 Kaolin 10I Titanium white pigment 5 rthe treated sheets when the coating has set are then similarly coated on the reverse side with the following composition Parts by weight.

Rosin oil 120 y Montan wax Canada balsam 150m Parafiin wax 150 Titanium white pigment 64 Magnesium oxi e 32 or with a composition consisting mainly of waxes and ot a non-tacky character.

The coated sheets may be mounted upon backing sheets of a suitably absorbent paper or not as desired but they will in any case be associated with a relatively porous,

support in formingthe stencil with the aid ot an ink which may consist essentially.

of a dilute solution of sulphuric acid suitlows or permits compositions which are not tacky or sticky but which are caused by the pressure applied locally in the steneilling operation to adhere to the backing.

A stencil sheet in accordance with the invention is illustrated by way of example in the accompanying drawing, in which 1 indicates a sheet of yoshino paper, 2 the coating of, a composition adapted to be rendered soluble bythe local application of suitable lquefying agents, 3 a coating ot a composition which when pressure is locally applied to the stencilsheet will be transferred to a support on which the stencil sheet is placed.

Having now described my invention, what I claim as new and desi're to secure by Letters Patent is 1. The method of duplicating with the aid of stencils which comprises applying locally to a sheet of highly porous material furnished with an ink-resisting coating and supported on a backing sheet an agent adapted to soften the coating and at the same time securing adhesion between the stencil sheet and the support or backing.

2. The method of duplicating with the aid of stencils `which comprises applying locally toa sheet of highly porous material furnished with an ink-resisting coating and supported on a backing sheet an agent adapted to soften the coating so that by subsequent treatment the portion of the coating so softened may be removed, while securing adhesion between the stencil sheet and the support or backing by the vpressure of the implement used in stencilizing the stencil sheet.

3. The method of duplicating' with the aid of stencils which comprises applying locally with the aid of a delineating implement to a sheet of highly porous material coated on one side with a composition of av character adapted to be rendered removable by the local application of a liquefying agent and coated on the other side with a transferable composition, while said sheet issupported on a backing, an agent. adapted to render soluble the first-mentioned coating.

4. The method of duplicating with the aid of stencils which comprises applying locally t0 a sheet of yoshino paper turnished'with an ink-resisting. coating and supported on a backing sheet an agent adapted to soften the coating and at the sam'e time securing adhesionbetween the stencil sheet and the supportor backing. l

5. rlhe method of duplicating with the aid of stencils which comprises applying locally to a sheet of yoshino paper furnished with an ink-resisting coating and supported on a backing sheet an agent adapted to' soften the coating so that by subsequent treatment the portion of the coating so softened may be removed, while securing adhesion between the stencil sheet and ythe support or backing by the pressure of the implement used in stencilizing the stencil sheet.

6. The method of duplicating with the aid of stencils which comprises applying locally with the aid of a delineating implement to a sheet of yoshino paper coated on one side with a composition of a character adapted to be rendered removable by the local application of a liquefying agent and coated on the other side with a transferable composition, while said sheet is supported on a backing, an agent adapted to render soluble the iirstmentioned coating.

7. A stencil sheet `for use in duplicating comprising a sheet of highly porous material, on one face of said sheet a coating of a material adapted under the action of pressure to adhere to a support on which the stencil sheet is placed in the operation of stencilizing, and on Ithe other face of said sheet a coating of a composition. adapted to'be liquefied by the local application of a liquefying agent.`

8. A stencil sheet for use in duplicating comprising a sheet of highly porous material, on one face of saidsheet a coating of material sufficiently adhesivev to adhere .tol a support in contact with which'the stencil sheet is secured in stencilizing adjacent to those points where pressure is applied to the sheet in the stencilizing operation and on the other face of said sheet a coating of a composition adapted to be liquefied by the local application of a liquefying agent.

9. A combined stencil sheet for use in duplicating comprisinga sheet of highly porous material, on one face of said sheet a coating` of a composition adapted to be liqueed by the local application of a liqueying agent, an absorbent backing sheet detachably connected therewith and a. film `ot adhesive material between the stencil sheet and the backing sheet.

l0. A. stencil sheet for use in duplicating comprising a sheet of highly porous material, on one face of said sheet a coating of a material adapted'under the action ot pressure to 'adhere to a support on which the stencil sheet is placed in the operation of stencilizing, on the other face of said sheet' a coating oi a composition .adapted to be liquefied by the local application of a liquefying agent and a backing sheet semipermanently7 connect-ed to the stencil sheet with one of its faces adjacent to the firstmentioned tace 'of the Stencil sheet.

11. stencil sheet for use in duplicating comprising a sheet of yoshino paper, on one face of said sheet a coating of a material adapted under the action of pressure to adhere to a support on which the stencil sheet is placed in the operation of stencilizing, and on the other face of said 'sheet a coating of a composition adapted to be liquefied lou cured inv stencilizing adjacent to those.

points where pressure is applied tothe sheet in the stencilizing operation and on the other face of said sheet a coating of a cornposition adapted to be liquefied by the local application of .a liquefying agent.

13. A combined stencil sheet for use in duplicating comprising a sheet of yoshino paper, on one face of said sheet a coating of a composition adapted to be liquefied by the local application of a liquefying agent, an absorbent backing sheet detachably connected therewith and a film of adhesive material between the stencil sheet and the backing sheet.

14. A stencil sheet for use in duplicating comprising a sheet of yoshino paper, on one face of said sheet a coating of a material adapted'under the action of pressure to adhere to a support on which the stencil sheet is placed in the operation of stencilizing, on the other face of; said sheet 'a coating of a composition adapted to be liquefied by the vlocal application of a liquefying agent and a backing sheet semi-permanently connected to the stencil sheet with one of its faces adjacent to the first-mentioned face .of the stencil sheet. 1

15. A stencil sheet for use in duplicating 'comprising a sheet of yoshino paper, on one face of said sheet a coating of a material adapted under the action of pressure to adhere to a support on which the stencil sheet is placed in the operation ot stencilizing,

and on the other face of said sheet a coating of a, gelatinous composition adapted to .be liqueiied by the local application of a liquefying agent. Y

16. A stencil sheet for use in duplicating comprising a sheet of yoshino paper, on one face of said sheet a coating of material sufficiently adhesive to adhere to a support in contact with which the stencil sheet is securedin stencilizing adj acenttothose points where pressure is applied to the sheet in the stencilizing operation 'and on the other face of said sheet a coating of aA gelatinous composition adapted to be liquefied by the local application of a liquefying agent.

17. A combined stencil sheet for use in duplicating comprising a sheet of yoshino paper, onvone face of said sheet a coating of a gelatinous composition adapted to be liquefied by the local application of a liquetying agent, an absorbent backing sheet detachably connected therewith and a' film of adhesive material between the stencil sheet and the backing sheet.

18. A stencil heet for use in duplicating comprising a sheet of yoshino paper, on one face of said sheet a coating of a material adapted under the'action of pressure to adhere to a support on which the stencil sheet is placed in the operation of stencilizing, on the other face of said sheet a coating of a gelatinous composition adapted-to 'be liquetied by the local' application of a. liquefying agent and a backing sheet semi-permanently connected to the stencil sheet with one of its faces adjacent to the first-mentioned face of DAVID GESTETNER. 

